The invention relates to a thread cutter, particularly a reversing chuck, with a spindle which can be withdrawn and inserted, and pressure-equalizing conduits.
When the spindle of such a thread cutter is pulled or withdrawn from a housing structure of the thread cutter, an underpressure is developed by means of which, in the case of the conventional construction of the pressure-equalizing conduits as continuous ventilation openings, emulsion and processing residues can be aspirated inwards. Moreover, due to such an underpressure, transmission oil can also reach parts of the thread cutter where it is not wanted.
To avoid intake of contaminants the pressure-equalization conduits may be sealed towards the outside, however, excess pressure can develop upon heating and uncontrollably shift, over piston surfaces, the zero position of the spindle even as far as into the idling or the reversing position. Moreover, switching forces are also distorted by excess pressure or underpressure.